关键词: 大涵道比涡扇发动机；涡轮过渡流道；一体化概念；支板；低压涡轮导叶

Abstract: In order to improve the aerodynamic performance of high bypass ratio turbofan engines ，reduce their fuel consumption and emissions，and meanwhile take the cost and weight into consideration，an integrated concept is proposed for the intermediate turbine duct(ITD) between high pressure turbine(HPT) and low pressure turbine(LPT). The new struts，mounted in the duct，replace the original struts and the following low pressure inlet guide vanes(IGV). That is to say，the new struts have to provide the downstream rotor blade row with suitable inlet conditions. A sample is designed and flow field analysis is performed through numerical simulation. The results show that the exit Mach number and tangential velocity of the new ITD are in good agreement with the original，which proves that the integrated design is valid. The total pressure loss of the new ITD is 4.3% at design point conditions，which is a little bit higher than the original(4.1%)，but it can adapt to off-design point conditions much more than the original，which reflects that it is superior in some ways.

Key words: High bypass ratio turbofan engine；Intermediate turbine duct；Integrated concept；Struts；Low pressure inlet guide vanes